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3 years ago

How do you know how many valence electrons are in a molecule?

Chemistry

2 answers:

telo118 [61]3 years ago

4 0

1. by making a atomic configuration
2.by making a table of shells of k.l.m.n....
that's all

Leno4ka [110]3 years ago

4 0

To know the number of valence electrons you must know the number of electrons in the outer shell .. In the periodic table there are 8 groups (which are the vertical columns) .. ignore the yellow ones for now which are the transition metals .. the group number is the number of electrons in the most outer shell of an atom .. so for example lithium and sodium are in group 1 so they have only 1 electron in their outer shell .. the valence electrons are the ones an atom looses or gains during a chemical reaction (atoms try to be stable by having 8 electrons in their outer most shell) .. for example atoms in group 1 have 1 electron in their outer shell that they want to loose so the valency is 1 .. In group 5 they need to become 8 so they gain 3 electrons so the valency is 3

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Question 2 (1 point) At the center of the atom is the electron. True False

Stells [14]

Answer:

False the electrons are on the outside of the atoms

Explanation:

5 0

3 years ago

Drag each item to indicate whether it is related to Aristotle's or Ptolemy's model of the solar system, or to both. Some items m

Romashka-Z-Leto [24]

Answer:

Aristotle's Model :

geocentric

planets fixed on nested spheres

Ptolemy's model:

geocentric

planets fixed on epicycles

accurately predicted the positions of the planets

Explanation:

Let's begin by the fact both models are geocentric and make a brief explanation of them:

Aristotle's Model :

Aristotle built his model based on observations and philosophical assumptions, not on measurements or calculations, then he mistakenly thought the Earth was the center of the universe.

So, according to this model, the universe was spherical and finite, with the Earth immobile at its center, composed of the four fundamental elements (made up of spherical layers): ground, water, air and fire; and the Sun along with the fixed planets in their respective concentric spheres (also called nested spheres) revolving around the Earth.

Ptolemy's model:

Ptolemy's model of the universe was also geocentric, placing the Earth motionless in the center of the known universe and was the accepted model for a long time during the Middle Ages.

In this sense, ccording to Ptolemy's model of the universe our planet remains stationary while the other planets, the Moon and the Sun describe complicated orbits around it (called epicycles).

However, this model predicted with an acceptable accuracy for that time the motion of the known planets, until Copernicus appeared with the revolutionary Heliocentric model.

5 0

3 years ago

What’s number 1, 2, 3 Major grade 6th grade

Maslowich

Answer:

1 is B

2 is A

3 is A

Explanation:

Hope you pass

8 0

2 years ago

What is the energy change if 84.0 g of calcium oxide (CaO) reacts with excess water in the following reaction?

pochemuha

The energy change if 84.0 g of CaO react with excess water is 98KJ of heat is released.

calculation
heat = number of moles x delta H

delta H = - 65.2 Kj/mol

first find the number of moles of CaO reacted

moles = mass/molar mass
the molar mass of CaO = 40 + 16= 56 g/mol
mass = 84 g
moles therefore = 84 g/56 g/mol =1.5 moles

Heat is therefore = 1.5 moles x -65.2 = - 97.8 Kj = -98 Kj

since sign is negative the energy is released

6 0

3 years ago

Natural atom of the same element may have the same _________?

Minchanka [31]

Answer:B

Explanation:

4 0

3 years ago

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